MiR-33a is a therapeutic target in SPG4-related hereditary spastic paraplegia human neurons.

Recent reports, including ours, have indicated that microRNA (miR)-33 located within the intron of sterol regulatory element binding protein (SREBP) 2 controls cholesterol homeostasis and can be a potential therapeutic target for the treatment of atherosclerosis. Here, we show that SPAST, which encodes a microtubule-severing protein called SPASTIN, was a novel target gene of miR-33 in human. Actually, the miR-33 binding site in the SPAST 3'-UTR is conserved not in mice but in mid to large mammals, and it is impossible to clarify the role of miR-33 on SPAST in mice. We demonstrated that inhibition of miR-33a, a major form of miR-33 in human neurons, via locked nucleic acid (LNA)-anti-miR ameliorated the pathological phenotype in hereditary spastic paraplegia (HSP)-SPG4 patient induced pluripotent stem cell (iPSC)-derived cortical neurons. Thus, miR-33a can be a potential therapeutic target for the treatment of HSP-SPG4.

Co-morbidity of progressive supranuclear palsy and amyotrophic lateral sclerosis: a clinical-pathological case report.

BACKGROUND: The coexistence of distinct neurodegenerative diseases in single cases has recently attracted greater attention. The phenotypic co-occurrence of progressive supranuclear palsy (PSP) and amyotrophic lateral sclerosis (ALS) has been documented in several cases. That said, the clinicopathological comorbidity of these two diseases has not been demonstrated. CASE PRESENTATION: A 77-year-old man presented with gait disturbance for 2 years, consistent with PSP with progressive gait freezing. At 79 years old, he developed muscle weakness compatible with ALS. The disease duration was 5 years after the onset of PSP and 5 months after the onset of ALS. Neuropathological findings demonstrated the coexistence of PSP and ALS. Immunohistochemical examination confirmed 4-repeat tauopathy, including globose-type neurofibrillary tangles, tufted astrocytes, and oligodendroglial coiled bodies as well as TAR DNA-binding protein 43 kDa pathology in association with upper and lower motor neuron degeneration. Immunoblotting showed hyperphosphorylated full-length 4-repeat tau bands (64 and 68 kDa) and C-terminal fragments (33 kDa), supporting the diagnosis of PSP and excluding other parkinsonian disorders, such as corticobasal degeneration. Genetic studies showed no abnormalities in genes currently known to be related to ALS or PSP. CONCLUSIONS: Our case demonstrates the clinicopathological comorbidity of PSP and ALS in a sporadic patient. The possibility of multiple proteinopathies should be considered when distinct symptoms develop during the disease course.

ALS5/SPG11/KIAA1840 mutations cause autosomal recessive axonal Charcot-Marie-Tooth disease.

Charcot-Marie-Tooth disease is a group of hereditary peripheral neuropathies that share clinical characteristics of progressive distal muscle weakness and atrophy, foot deformities, distal sensory loss, as well as diminished tendon reflexes. Hundreds of causative DNA changes have been found, but much of the genetic basis of the disease is still unexplained. Mutations in the ALS5/SPG11/KIAA1840 gene are a frequent cause of autosomal recessive hereditary spastic paraplegia with thin corpus callosum and peripheral axonal neuropathy, and account for ∼ 40% of autosomal recessive juvenile amyotrophic lateral sclerosis. The overlap of axonal Charcot-Marie-Tooth disease with both diseases, as well as the common autosomal recessive inheritance pattern of thin corpus callosum and axonal Charcot-Marie-Tooth disease in three related patients, prompted us to analyse the ALS5/SPG11/KIAA1840 gene in affected individuals with autosomal recessive axonal Charcot-Marie-Tooth disease. We investigated 28 unrelated families with autosomal recessive axonal Charcot-Marie-Tooth disease defined by clinical, electrophysiological, as well as pathological evaluation. Besides, we screened for all the known genes related to axonal autosomal recessive Charcot-Marie-Tooth disease (CMT2A2/HMSN2A2/MFN2, CMT2B1/LMNA, CMT2B2/MED25, CMT2B5/NEFL, ARCMT2F/dHMN2B/HSPB1, CMT2K/GDAP1, CMT2P/LRSAM1, CMT2R/TRIM2, CMT2S/IGHMBP2, CMT2T/HSJ1, CMTRID/COX6A1, ARAN-NM/HINT and GAN/GAN), for the genes related to autosomal recessive hereditary spastic paraplegia with thin corpus callosum and axonal peripheral neuropathy (SPG7/PGN, SPG15/ZFYVE26, SPG21/ACP33, SPG35/FA2H, SPG46/GBA2, SPG55/C12orf65 and SPG56/CYP2U1), as well as for the causative gene of peripheral neuropathy with or without agenesis of the corpus callosum (SLC12A6). Mitochondrial disorders related to Charcot-Marie-Tooth disease type 2 were also excluded by sequencing POLG and TYMP genes. An additional locus for autosomal recessive Charcot-Marie-Tooth disease type 2H on chromosome 8q13-21.1 was excluded by linkage analysis. Pedigrees originated in Italy, Brazil, Canada, England, Iran, and Japan. Interestingly, we identified 15 ALS5/SPG11/KIAA1840 mutations in 12 families (two sequence variants were never reported before, p.Gln198* and p.Pro2212fs*5). No large deletions/duplications were detected in these patients. The novel mutations seemed to be pathogenic since they co-segregated with the disease in all pedigrees and were absent in 300 unrelated controls. Furthermore, in silico analysis predicted their pathogenic effect. Our results indicate that ALS5/SPG11/KIAA1840 is the causative gene of a wide spectrum of clinical features, including autosomal recessive axonal Charcot-Marie-Tooth disease.

A homozygous mutation of VWA3B causes cerebellar ataxia with intellectual disability.

BACKGROUND: Hereditary cerebellar ataxia constitutes a heterogeneous group of neurodegenerative disorders, occasionally accompanied by other neurological features. Genetic defects remain to be elucidated in approximately 40% of hereditary cerebellar ataxia cases in Japan. We attempted to identify the gene responsible for autosomal recessive cerebellar ataxia with intellectual disability. METHODS: The present study involved three patients in a consanguineous Japanese family. Neurological examination and gene analyses were performed in all family members. We performed genome-wide linkage analysis including single nucleotide polymorphism arrays, copy-number variation analysis and whole exome sequencing. To clarify the functional alteration resulting from the identified mutation, we performed cell viability assay of cultured cells expressing mutant protein. RESULTS: One homozygous region shared among the three patients on chromosomes 2p16.1-2q12.3 was identified. Using whole exome sequencing, six homozygous variants in genes in the region were detected. Only one variant, VWA3B c.A1865C, results in a change of a highly conserved amino acid (p.K622T) and was not present in control samples. VWA3B encodes a von Willebrand Factor A Domain-Containing Protein 3B with ubiquitous expression, including the cerebellum. The viability of cultured cells expressing the specific K622T mutation was proved to decrease through the activation of apoptotic pathway. CONCLUSIONS: Mutated VWA3B was found to be likely associated with cerebellar degeneration with intellectual disability. Although a rare cause of cerebellar degeneration, these findings indicate a critical role for VWA3B in the apoptosis pathway in neuronal tissues.

Extranodal NK/T-cell lymphoma, nasal type, manifesting as rapidly progressive dementia without any mass or enhancing brain lesion.

Among the many potential etiologies for rapidly progressive dementia (RPD), primary central nervous system extranodal NK/T-cell lymphoma, nasal-type (ENKL) is a rare entity. We present the first reported case of autopsy-proven RPD due to ENKL without any mass or enhancing lesion of the brain. A 54-year-old immunocompetent man presented with RPD, myoclonus and ataxia. The mini-mental state examination (MMSE) score was 22/30. His brain MRI revealed progressive brain atrophy without gadolinium enhancement or mass lesion. Five months after the initial evaluation, cognitive impairment further worsened with an MMSE score of 3/30. At the advanced stage, lumbar MRI showed swollen cauda equina with gadolinium enhancement. The number of Epstein-Barr virus (EBV) DNA in cerebrospinal fluid had gradually increased. Twelve months after onset, the patient died of respiratory failure. Pathological findings revealed that lymphoma cells had diffusely invaded the meninges, parenchyma of the brain, spinal cord and cauda equina. Cells were positive for CD3, CD56 and EBV-encoded small RNAs and negative for CD20. No evidence of malignancy was identified in the visceral organs. This report indicates that ENKL should be recognized as one of the rare causes of RPD. Early testing for EBV-DNA in cerebrospinal fluid and imaging of cauda equina would be useful diagnostic tools.

The neuronal sortilin-related receptor SORL1 is genetically associated with Alzheimer disease.

The recycling of the amyloid precursor protein (APP) from the cell surface via the endocytic pathways plays a key role in the generation of amyloid beta peptide (Abeta) in Alzheimer disease. We report here that inherited variants in the SORL1 neuronal sorting receptor are associated with late-onset Alzheimer disease. These variants, which occur in at least two different clusters of intronic sequences within the SORL1 gene (also known as LR11 or SORLA) may regulate tissue-specific expression of SORL1. We also show that SORL1 directs trafficking of APP into recycling pathways and that when SORL1 is underexpressed, APP is sorted into Abeta-generating compartments. These data suggest that inherited or acquired changes in SORL1 expression or function are mechanistically involved in causing Alzheimer disease.

The TRK-fused gene is mutated in hereditary motor and sensory neuropathy with proximal dominant involvement.

Hereditary motor and sensory neuropathy with proximal dominant involvement (HMSN-P) is an autosomal-dominant neurodegenerative disorder characterized by widespread fasciculations, proximal-predominant muscle weakness, and atrophy followed by distal sensory involvement. To date, large families affected by HMSN-P have been reported from two different regions in Japan. Linkage and haplotype analyses of two previously reported families and two new families with the use of high-density SNP arrays further defined the minimum candidate region of 3.3 Mb in chromosomal region 3q12. Exome sequencing showed an identical c.854C>T (p.Pro285Leu) mutation in the TRK-fused gene (TFG) in the four families. Detailed haplotype analysis suggested two independent origins of the mutation. Pathological studies of an autopsied patient revealed TFG- and ubiquitin-immunopositive cytoplasmic inclusions in the spinal and cortical motor neurons. Fragmentation of the Golgi apparatus, a frequent finding in amyotrophic lateral sclerosis, was also observed in the motor neurons with inclusion bodies. Moreover, TAR DNA-binding protein 43 kDa (TDP-43)-positive cytoplasmic inclusions were also demonstrated. In cultured cells expressing mutant TFG, cytoplasmic aggregation of TDP-43 was demonstrated. These findings indicate that formation of TFG-containing cytoplasmic inclusions and concomitant mislocalization of TDP-43 underlie motor neuron degeneration in HMSN-P. Pathological overlap of proteinopathies involving TFG and TDP-43 highlights a new pathway leading to motor neuron degeneration.

Defects in the striatal neuropeptide Y system in X-linked dystonia-parkinsonism.

Neuropeptide Y is a novel bioactive substance that plays a role in the modulation of neurogenesis and neurotransmitter release, and thereby exerts a protective influence against neurodegeneration. Using a sensitive immunohistochemical method with a tyramide signal amplification protocol, we performed a post-mortem analysis to determine the striatal localization profile of neuropeptide Y in neurologically normal individuals and in patients with X-linked dystonia-parkinsonism, a major representative of the neurodegenerative diseases that primarily involve the striatum. All of the patients examined were genetically verified as having X-linked dystonia-parkinsonism. In normal individuals, we found a scattered distribution of neuropeptide Y-positive neurons and numerous nerve fibres labelled for neuropeptide Y in the striatum. Of particular interest was a differential localization of neuropeptide Y immunoreactivity in the striatal compartments, with a heightened density of neuropeptide Y labelling in the matrix compartment relative to the striosomes. In patients with X-linked dystonia-parkinsonism, we found a significant decrease in the number of neuropeptide Y-positive cells accompanied by a marked loss of their nerve fibres in the caudate nucleus and putamen. The patients with X-linked dystonia-parkinsonism also showed a lack of neuropeptide Y labelling in the subventricular zone, where a marked loss of progenitor cells that express proliferating cell nuclear antigen was found. Our results indicate a neostriatal defect of the neuropeptide Y system in patients with X-linked dystonia-parkinsonism, suggesting its possible implication in the mechanism by which a progressive loss of striatal neurons occurs in X-linked dystonia-parkinsonism.

Deep brain stimulation of the thalamic ventral lateral anterior nucleus for DYT6 dystonia.

BACKGROUND: A missense mutation of the THAP1 gene results in DYT6 primary dystonia. While deep brain stimulation (DBS) of the internal globus pallidus (GPi) is effective in treating primary dystonia, recent reports indicate that GPi DBS is only mildly effective for DYT6 dystonia. OBJECTIVE: To describe a patient with DYT6 dystonia who underwent thalamic ventral lateral anterior (VLa) nucleus DBS. PATIENT: A 35-year-old Japanese man had been experiencing upper limb dystonia and spasmodic dysphonia since the age of 15. His dystonic symptoms progressed to generalized dystonia. He was diagnosed as having DYT6 dystonia with mutations in the THAP1 gene. Because his dystonic symptoms were refractory to pharmacotherapy and pallidal DBS, he underwent thalamic VLa DBS. RESULTS: Continuous bilateral VLa stimulation with optimal parameter settings ameliorated the patient's dystonic symptoms. At the 2-year follow-up, his Burke-Fahn-Marsden Dystonia Rating Scale total score decreased from 71 to 11, an improvement of more than 80%. CONCLUSIONS: The thalamic VLa nucleus could serve as an alternative target in DBS therapy for DYT6 dystonia.

Reduced histone H3K4 trimethylation in oral mucosa of patients with DYT-KMT2B.

BACKGROUND: DYT-KMT2B, also known as DYT28, is a childhood-onset hereditary dystonia caused by KMT2B mutation. The pathogenesis of DYT-KMT2B involves haploinsufficiency of KMT2B, an enzyme that catalyzes specific histone methylation (H3K4me3). Dysmorphic features in patients with DYT-KMT2B suggest that KMT2B dysfunction may extend beyond the neuronal system. Therefore, valuable diagnostic insights may be obtained from readily available tissue samples. OBJECTIVES: To explore the altered H3K4me3 levels in non-neural tissue of DYT-KMT2B patients. METHODS: A database analysis was performed to determine in which parts of the body and in which cells KMT2B is highly expressed. Twelve clinically and genetically diagnosed patients with DYT-KMT2B and 12 control subjects participated in this study. Oral mucosa-derived purified histone proteins were analyzed using Western blotting with anti-H3K4me3 and anti-H4 antibodies. RESULTS: Higher expression of KMT2B was observed in oral keratinocytes and gingival fibroblasts, constituting the oral mucosa. In oral mucosa analyses, DYT-KMT2B cases exhibited markedly reduced H3K4me3 levels compared with the controls. Using a cutoff window of 0.90-0.98, the H3K4me3/H4 expression ratio was able to distinguish patient groups. CONCLUSIONS: Oral mucosa H3K4me3 analysis is currently not sufficient as a diagnostic tool for DYT-KMT2B, but has the advantage for screening test since it is a non-invasive means.

Arterial stiffness and progressive neurological deficit in patients with acute deep subcortical infarction.

BACKGROUND AND PURPOSE: The mechanism of progressive neurological deficit (PND) in patients with ischemic stroke remains unclear. The aim of this study was to clarify whether arterial stiffness, a marker of vascular endothelial impairment and arteriosclerosis, is associated with PND in patients with acute deep subcortical infarction. METHODS: We evaluated 156 consecutive first-ever ischemic stroke patients with acute deep subcortical infarction. PND was defined as an increment of ≥2 points in the National Institute of Health Stroke Scale score or an increase of ≥1 point in the limb weakness score within 7 days of stroke onset. Patients were assessed for risk factors, and infarct size was measured on initial diffusion-weighted magnetic resonance imaging. We measured brachial-ankle pulse wave velocity (baPWV) as a marker of arterial stiffness. We divided patients into 2 groups according to the presence or absence of PND to compare their clinical characteristics. RESULTS: Fifty-two patients (33%) had PND, and baPWV was significantly higher in patients with than in those without PND. The baPWV cut-off value for PND was 18.24 m/s, with 90% sensitivity and 47% specificity. In multivariable logistic regression analysis, high baPWV (≥18.24 m/s; odds ratio, 8.22; 95% confidence interval, 2.55-31.9), large infarct size (≥15 mm; odds ratio, 2.76; 95% confidence interval, 1.01-7.92), and ≥3 infarct slices on serial axial diffusion-weighted imaging (odds ratio, 3.38; 95% confidence interval, 1.22-10.0) were independently associated with PND. CONCLUSIONS: Arterial stiffness indicated by baPWV is independently associated with PND in patients with acute deep subcortical infarction.

TMP21 is a presenilin complex component that modulates gamma-secretase but not epsilon-secretase activity.

The presenilin proteins (PS1 and PS2) and their interacting partners nicastrin, aph-1 (refs 4, 5) and pen-2 (ref. 5) form a series of high-molecular-mass, membrane-bound protein complexes that are necessary for gamma-secretase and epsilon-secretase cleavage of selected type 1 transmembrane proteins, including the amyloid precursor protein, Notch and cadherins. Modest cleavage activity can be generated by reconstituting these four proteins in yeast and Spodoptera frugiperda (sf9) cells. However, a critical but unanswered question about the biology of the presenilin complexes is how their activity is modulated in terms of substrate specificity and/or relative activities at the gamma and epsilon sites. A corollary to this question is whether additional proteins in the presenilin complexes might subsume these putative regulatory functions. The hypothesis that additional proteins might exist in the presenilin complexes is supported by the fact that enzymatically active complexes have a mass that is much greater than predicted for a 1:1:1:1 stoichiometric complex (at least 650 kDa observed, compared with about 220 kDa predicted). To address these questions we undertook a search for presenilin-interacting proteins that differentially affected gamma- and epsilon-site cleavage events. Here we report that TMP21, a member of the p24 cargo protein family, is a component of presenilin complexes and differentially regulates gamma-secretase cleavage without affecting epsilon-secretase activity.

Increased brachial-ankle pulse wave velocity is independently associated with white matter hyperintensities.

BACKGROUND: White matter hyperintensities (WMHs) are a risk factor for stroke. Their etiology is considered to be cerebral microvascular abnormality. However, the association between WMHs and arteriosclerosis is not yet clear. The aim of this hospital-based cohort study was to identify the arteriosclerotic characteristics associated with WMHs. METHODS: We cross-sectionally included 240 consecutive patients with no history of stroke. We measured the brachial-ankle pulse wave velocity (baPWV), ankle brachial pressure index, and intima-media thickness of the common carotid artery, and we performed magnetic resonance brain imaging. WMHs were defined as periventricular hyperintensity (Fazekas grade ≥3) and/or separate deep white matter hyperintense signals (Fazekas grade ≥2). We determined the prevalence of WMHs, silent brain infarction (SBI), hypertension, hypercholesterolemia, diabetes mellitus, ischemic heart disease, and smoking. We compared 2 groups of patients, defined by the presence or absence of WMHs, using multiple logistic regression analyses. RESULTS: In multivariable analysis, SBI (OR 3.38; 95% CI 1.52-7.72), hypertension (OR 2.23; 95% CI 1.03-5.15), female sex (OR 1.95; 95% CI 1.03-3.76), baPWV (OR 1.12; 95% CI 1.02-1.23), and age (OR 1.09; 95% CI 1.04-1.14) were independently associated with WMHs. CONCLUSIONS: An increased baPWV is associated with WMHs. Management of increased baPWV may help to prevent the progression of WMHs and stroke.

SPATACSIN mutations cause autosomal recessive juvenile amyotrophic lateral sclerosis.

The mutation of the spatacsin gene is the single most common cause of autosomal recessive hereditary spastic paraplegia with thin corpus callosum. Common clinical, pathological and genetic features between amyotrophic lateral sclerosis and hereditary spastic paraplegia motivated us to investigate 25 families with autosomal recessive juvenile amyotrophic lateral sclerosis and long-term survival for mutations in the spatascin gene. The inclusion criterion was a diagnosis of clinically definite amyotrophic lateral sclerosis according to the revised El Escorial criteria. The exclusion criterion was a diagnosis of hereditary spastic paraplegia with thin corpus callosum in line with an established protocol. Additional pathological and genetic evaluations were also performed. Surprisingly, 12 sequence alterations in the spatacsin gene (one of which is novel, IVS30 + 1 G > A) were identified in 10 unrelated pedigrees with autosomal recessive juvenile amyotrophic lateral sclerosis and long-term survival. The countries of origin of these families were Italy, Brazil, Canada, Japan and Turkey. The variants seemed to be pathogenic since they co-segregated with the disease in all pedigrees, were absent in controls and were associated with amyotrophic lateral sclerosis neuropathology in one member of one of these families for whom central nervous system tissue was available. Our study indicates that mutations in the spatascin gene could cause a much wider spectrum of clinical features than previously recognized, including autosomal recessive juvenile amyotrophic lateral sclerosis.

Clinical features of a first-ever lacunar infarction in Japanese patients: poor outcome in females.

Lacunar infarction (LI) remains an important stroke subtype in Japan. The aim of this study was to investigate the characteristics of outcome determinants in LI. This study was a single center observational study and included 163 consecutive patients (108 male, 55 female; mean age 69 years). The National Institutes of Health Stroke Scale (NIHSS) score on admission and the modified Rankin scale (mRS) score at discharge were used to evaluate stroke severity. We determined the location of the infarct, the grade of white matter hyperintensity (WMH), and the prevalence of silent brain infarcts, hypertension, hypercholesterolemia, diabetes mellitus, ischemic heart disease, and smoking. We compared 2 groups, good outcome (mRS score 0-2) and poor outcome (mRS score 3-5), using multiple logistic regression analysis. We found significant differences between the 2 groups according to female sex (P = .04), WMH (P = .04), and NIHSS score (P < .001). After multivariate analysis, female sex (odds ratio [OR] = 3.4, 95% confidence interval [CI] = 1.1-11.4; P = .03), and NIHSS score (OR = 2.3, 95% CI = 1.7-3.3; P < .001) were independently associated with poor outcome. Elderly onset, poor outcome, and hypercholesterolemia were more common in female patients, whereas smoking was more prevalent in males. Our data indicate that sex differences exist in Japanese LI patients with regard to risk factors and outcome. The treatment of risk factors based on sex differences is important to the management of LI.

Monozygotic twins with DYT-TOR1A showing jerking movements and levodopa responsiveness.

BACKGROUND: DYT-TOR1A is caused by a GAG deletion in the TOR1A gene. While it usually manifests as early-onset dystonia, its phenotype is extremely diverse, even within one family. Recent reports have revealed that some DYT-TOR1A cases have novel mutations in the TOR1A gene while others have mutations in both TOR1A and another DYT gene (THAP1 or SGCE). Our understanding of the correlation between genotype and phenotype is becoming increasingly complicated. CASE PRESENTATIONS: Here, we report on monozygotic twins who developed dystonia in childhood. The two children had different presentations in terms of onset age and dominant disturbances, but both exhibited marked diurnal fluctuation and jerking movements of the limbs as well as levodopa/levodopa-carbidopa responsiveness. These features are commonly associated with DYT/PARK-GCH1 and DYT-SGCE, yet these twins had no mutations in the GCH1 or SGCE genes. Whole exome sequencing eventually revealed a single GAG deletion in the TOR1A gene. CONCLUSION: Monozygotic twins whose only mutation was a GAG deletion in TOR1A exhibited DYT/PARK-GCH1-asssociated features and jerking movements reminiscent of myoclonus. This finding may expand the spectrum of phenotypes associated with DYT-TOR1A, and suggests that levodopa has potential as a treatment for DYT-TOR1A with DYT/PARK-GCH1-associated features.

Ataxia with vitamin E deficiency in the Philippines†: A case report of two siblings.

Here we report two siblings with ataxia and peripheral neuropathy. One patient showed head tremors. Genetic analysis revealed a mutation in the hepatic α-tocopherol transfer protein (α-TTP) gene (TTPA) on chromosome 8q13. They were diagnosed with ataxia with vitamin E deficiency which is firstly reported in the Philippines. As the symptoms of ataxia with vitamin E deficiency can be alleviated with lifelong vitamin E administration, differential diagnosis from similar syndromes is important. In addition, ataxia with vitamin E deficiency causes movement disorders. Therefore, a common hereditary disease in the Philippines, X-linked dystonia-parkinsonism, could be another differential diagnosis. The Philippines is an archipelago comprising 7,107 islands, and the prevalence of rare hereditary diseases among the populations of small islands is still unclear. For neurologists, establishing a system of genetic diagnosis and counseling in rural areas remains challenging. These unresolved problems should be addressed in the near future. J. Med. Invest. 68 : 400-403, August, 2021.